Effects of breed, feed level and conditioning time on the tenderness of pork

Moringa oleifera leaf improves meat quality by modulating intestinal microbes in white feather broilers

Moringa oleifera addition to animal diets can improve the growth performance, intestinal health, and immunity of animals, without adverse effects. We investigated the effects of Moringa oleifera on the growth performance, meat quality, and intestinal health of broilers. Moringa oleifera and fermented Moringa oleifera could improve the flesh color and breast muscle tenderness of broilers (p < 0.05). The contents of essential amino acids, unsaturated fatty acids, ΣMUFA, P/S and n-3 ratio in breast muscle of broilers were dose-increased, and the effect of fermented Moringa oleifera was better. Moringa oleifera and fermented Moringa oleifera regulated chicken flavor metabolism by increasing the relative abundance and Short-chain fatty acid (SCFA) contents of Bacteroides, Spirillum, and lactic acid bacteria. Overall, supplementation with 1 % fermented Moringa oleifera can significantly increase essential amino acid and unsaturated fatty acid contents in broilers and participate in the synthesis and transformation of amino acids and fatty acids regulated by beneficial bacteria.

Sow-Offspring Diets Supplemented with Probiotics and Synbiotics Are Associated with Offspring's Growth Performance and Meat Quality

Probiotics and synbiotics supplementation have been shown to play potential roles in animal production. The present study aimed to evaluate the effects of dietary probiotics and synbiotics supplementation to sows during gestation and lactation and to offspring pigs (sow-offspring) on offspring pigs' growth performance and meat quality. Sixty-four healthy Bama mini-pigs were selected and randomly allocated into four groups after mating: the control, antibiotics, probiotics, and synbiotics groups. After weaning, two offspring pigs per litter were selected, and four offspring pigs from two litters were merged into one pen. The offspring pigs were fed a basal diet and the same feed additive according to their corresponding sows, representing the control group (Con group), sow-offspring antibiotics group (S-OA group), sow-offspring probiotics group (S-OP group), and sow-offspring synbiotics group (S-OS group). Eight pigs per group were euthanized and sampled at 65, 95, and 125 d old for further analyses. Our findings showed that probiotics supplementation in sow-offspring diets promoted growth and feed intake of offspring pigs during 95-125 d old. Moreover, sow-offspring diets supplemented with probiotics and synbiotics altered meat quality (meat color, pH_45min, pH_24h, drip loss, cooking yield, and shear force), plasma UN and AMM levels, and gene expressions associated with muscle-fiber types (MyHCI, MyHCIIa, MyHCIIx, and MyHCIIb) and muscle growth and development (Myf5, Myf6, MyoD, and MyoG). This study provides a theoretical basis for the maternal-offspring integration regulation of meat quality by dietary probiotics and synbiotics supplementation.

Dietary Effect of Brevibacillus laterosporus S62-9 on Chicken Meat Quality, Amino Acid Profile, and Volatile Compounds

Probiotics are being used in diets to improve the quality of chicken meat. The aim of the study was to investigate the effects of dietary supplementation with Brevibacillus laterosporus S62-9 microbial agent on the meat quality, amino acids, and volatile compounds of chicken. The experiment was carried out with 160 1-day-old Arbor Acres male broiler chickens, rearing for 42 d. The chickens were randomly divided into two groups of 8 replicates each, with 10 chickens in each group. No supplement was added to the basal diet in the control group and Brevibacillus laterosporus S62-9 microbial agent was added to the diet of the experimental group. At the end of the experiment, the meat quality, meat chemical composition, amino acid composition, and volatile compounds of chicken were determined. The results showed that pH (p < 0.05), pressing loss (p < 0.05), cooking loss (p < 0.05), and shear force (p < 0.01) were notably decreased, the percentage of breast meat (p < 0.01), protein content (p < 0.05) were visibly increased, and remarkable changes were observed in the amino acid composition (change in seven amino acids) and volatile compounds profile (an increase of about 20-fold in the contents of 1-octen-3-ol and hexanal). In summary, it was found that Brevibacillus laterosporus S62-9 microbial agent can be used as a novel and effective feed supplement to improve the nutritional quality and flavor characteristics of broilers.

Evaluation of coat color inheritance and production performance for crossbreed from Chinese indigenous Chenghua pig crossbred with Berkshire

Objective

This work was to determine coat inheritance and evaluate production performance for crossbred pigs from Berkshire×Chenghua (BC) compared with Chinese indigenous Chenghua (CH) pigs.

Methods

The coat color phenotypes were recorded for more than 16,000 pigs, and the genotypes of melanocortin 1 receptor (MCIR) gene were identified by sequencing. The reproductive performance of 927 crossbred BC F4 gilts and 320 purebred CH gilts was recorded. Sixty pigs of each breed were randomly selected at approximately 60 days of age to determine growth performance during fattening period, which lasted for 150 days for BC pigs and 240 days for CH pigs. At the end of the fattening period, 30 pigs of each breed were slaughtered to determine carcass composition and meat quality.

Results

The coat color of BC pigs exhibits a “dominant black” hereditary pattern, and all piglets derived from boars or sows genotyped E^D1E^D1 homozygous for MC1R gene showed a uniform black coat phenotype. The BC F4 gilts displayed a good reproductive performance, showing a higher litter and tear size and were heavier at farrowing litter and at weaning litter than the CH gilts, but they reached puberty later than the CH gilts. BC F4 pigs exhibited improved growth and carcass characteristics with a higher average daily live weight gain, lower feed-to-gain ratio, and higher carcass lean meat rate than CH pigs. Like CH pigs, BC F4 pigs produced superior meat-quality characteristics, showing ideal pH and meat-color values, high intramuscular fat content and water-holding capacity, and acceptable muscle-fiber parameters. C18:1, C16:0, C18:0, and C18:2 were the main fatty acids in M. longissimus lumborum in the two breeds, and a remarkably high polyunsaturated/saturated fatty acid ratio of ~0.39 was observed in the BC F4 pigs.

Conclusion

The BC F4 pigs exhibit a uniform black coat pattern and acceptable total production performance.

Review: Pork quality attributes from farm to fork. Part I. Carcass and fresh meat

This work considers all factors along the production chain from farm to fork influencing the quality of fresh pork and processed products. Pork quality is multidimensional and comprises various attributes: commercial value of carcasses, meat organoleptic, nutritional, technological (i.e. suitability for processing and storage) properties, convenience, and societal image. The latter denotes cultural, ethical (including animal welfare) and environmental dimensions related to pork production, including geographical origin, all of which influence societal perceptions for pork. This review covers the impact of production factors, slaughter methods, carcass processing, and post mortem ageing on fresh meat quality. The impact on pork quality from some of these factors are now well documented and clearly established (e.g. genetics and pork technological attributes; diet and lipid profile; preslaughter and slaughter conditions and pork technological or organoleptic attributes…). Gaps in scientific knowledge are also identified, including the need for a better understanding of regulatory pathways for oxidative stress in vivo and post mortem that can contribute to optimise pork organoleptic and nutritional attributes and its suitability for processing and storage. This review highlights the strong interactions between primary production factors on pork quality attributes. Interactions are particularly marked in alternative production systems, in which synergies between factors can lead to specific quality characteristics that can be used to market pork at a premium as branded products. There are also antagonisms between quality attributes, namely between carcass commercial value and pork technological and organoleptic properties, between nutritional attributes and processing and storage suitability of fat tissues, between societal image and pork technological attributes in outdoor production systems, and between societal image (better welfare) and organoleptic attributes (risk for boar taint) in entire male production. Further research is needed to better understand the effects of some specific production factors and their interactions on quality attributes. A holistic approach with the use of multicriteria analyses can help to work out the trade-offs between pork quality attributes and between stakeholders (farmer, slaughterhouse or processing plant, consumers, citizens …) whose priorities may differ.

Dietary Supplementation With Chlorogenic Acid Derived From Lonicera macranthoides Hand-Mazz Improves Meat Quality and Muscle Fiber Characteristics of Finishing Pigs via Enhancement of Antioxidant Capacity

Chlorogenic acid (CGA), one of the most abundant polyphenol compounds in nature, is regarded as a potential feed additive to promote animal health and enhance the meat products’ quality via its various biological properties. The current study aims: (1) to determine whether dietary CGA supplementation improves meat quality and muscle fiber characteristics, and (2) to ascertain whether the corresponding improvement is associated with enhancing the antioxidant capacity of the finishing pigs. Thirty-two (Large × White × Landrace) finishing pigs with an average initial body weight of 71.89 ± 0.92 kg were allotted to 4 groups, and each was fed diets supplemented with 0, 0.02, 0.04, or 0.08% (weight/weight) of CGA. The meat quality traits, muscle fiber characteristics, and the serum and muscle antioxidant capacity were assessed. Results suggested that, compared with the control group, dietary CGA supplementation at a level of 0.04% significantly decreased the b^∗ value and distinctly increased the inosinic acid content of longissimus dorsi (LD) and biceps femoris (BF) muscles (P < 0.01). Moreover, dietary supplementation with 0.04% of CGA markedly improved the amino acid composition of LD and BF muscles, as well as augmented the mRNA abundance of Nrf-2, GPX-1, MyoD, MyoG, and oxidative muscle fiber (I and IIa) in LD muscle (P < 0.05). This result indicates that a diet supplemented with 0.04% of CGA promotes myogenesis and induces a transformation toward more oxidative muscle fibers in LD muscle, subsequently improving meat quality. Besides, dietary supplementation with 0.02% and 0.04% of CGA notably enhanced the serum GSH-PX level (P < 0.01). Considering all these effects are closely related to the alteration of antioxidant activities of the finishing pigs, the underlying metabolism is likely connected to the boosting of their antioxidant capacity induced by dietary CGA.

Leptin receptor and fatty acid desaturase-2 gene variants affect fat, color and production profile of dry-cured hams

The effects of LEPR (rs709596309C > T) and FADS2 (rs321384923A > G) single nucleotide polymorphisms on production and quality attributes in purebred Duroc dry-cured hams were examined. As compared to LEPR-C- hams, the LEPR-TT hams had more intramuscular fat (+2.2% dry matter, P < 0.01). As a result, they showed higher saturated (+1.54%, P < 0.01) and lower polyunsaturated (-1.05%, P < 0.01) fatty acids content and were brighter (L*: +1.07, P < 0.05) and yellower (b*: +0.78, P < 0.01). The FADS2-A allele enhanced the C20:4n-6 to C18:2n-6 ratio but did not affect either fat content or color coordinates. However, hams carrying the FADS2-A allele reached the target weight loss earlier, thereby spending less time in seasoning (-8.4 d, P < 0.01). Thus, production batches could be arranged by genotype, with longer manufacturing times for fatter LEPR-TT and shorter times for FADS2-A- hams. These results confirm that genetic markers validated in raw pork are effective in dry-cured ham, but also stress that product-specific validations are still needed to unravel specific outcomes.

Association between single nucleotide polymorphisms in GPAT1 locus and pork quality in pigs

GPAT1 gene is considered to be a genetic marker for intramuscular fat content. The GPAT enzymes catalyze the first step in triacylglycerol synthesis. In the present study, the search for polymorphisms within the pig GPAT1 gene locus as well as association analyses between SNPs and meat quality traits were performed. The association analysis demonstrated that g.133513422C > T polymorphism affected IMF content in LL, SEMI post-mortem pH and shear force of cooked LL (p ≤ .05). While the association of g.133476803 T > C polymorphism was shown concerning IMF content, meat color (L*), shear force and energy of raw meat as well as some meat texture parameters (hardness, springiness, chewiness) (p ≤ .05). The g.133476733C > T SNP was significantly associated with LL 24 h post-mortem pH, raw meat toughness and TPA hardness and chewiness (p ≤ .05). The obtained results are promising but to confirm if the GPAT1 gene can be considered to be a genetic marker for improving the quality of pork, further research is required.

Effects of dietary apple polyphenol supplementation on carcass traits, meat quality, muscle amino acid and fatty acid composition in finishing pigs

As health awareness is increasing, consumers have changed their focus with a desire to purchase safer, healthier, and higher quality and nutritional value meat. The aim of this study was to investigate whether dietary apple polyphenol (APP) supplementation in finishing pigs could provide pork with high quality and nutritional value. In the present study, 36 castrated Duroc × Landrace × Yorkshire pigs with an average body weight of 71.25 ± 2.40 kg were randomly divided into three treatments and fed with a basal diet supplemented with 0, 400, or 800 mg kg^-1 APPs for 7 weeks. The results showed that dietary 800 mg kg^-1 APP supplementation not only decreased backfat thickness and abdominal adipose tissue index but also decreased L* (lightness) and b* (yellowness) in the longissimus dorsi (LD) muscle. The LD muscle crude protein content, the proportions of essential amino acids, flavor amino acids, and total amino acids, as well as the amino acid transporter (SLC7A1, SLC7A2, SLC7A7, SLC1A2) mRNA levels were increased by 800 mg kg^-1 APPs. The proportions of docosahexaenoic acid and n-3 polyunsaturated fatty acid (PUFA) and the ratio of PUFA to saturated fatty acid in LD muscle were increased by 400 mg kg^-1 APPs. Meanwhile, dietary 400 mg kg^-1 and 800 mg kg^-1 APP supplementation decreased the contents of blood urea nitrogen and total cholesterol, as well as increased the content of inosinic acid in LD muscle. In conclusion, these results suggested that dietary 800 mg kg^-1 APP supplementation improved the carcass traits, meat color, and meat flavor in finishing pigs. These results also suggested that dietary 400 mg kg^-1 and 800 mg kg^-1 APP supplementation improved the meat nutritional value in finishing pigs. The present study provides effective evidence for the application of APP supplementation for healthy high-quality and nutritional value pork production.

Effect of visual marbling levels in pork loins on meat quality and Thai consumer acceptance and purchase intent

Objective

We investigated visual marbling level (VML) influence on pork loin physicochemical traits, consumer palatability responses, VML liking, purchase intent, and their relationships.

Methods

For each of five slaughtering dates, at 24-h postmortem, nine paired Duroc castrated male boneless Longissimus dorsi (LD) muscles were categorized into low (LM, score 1-2, n=3), medium (MM, score 3-4, n=3), and high (HM, score 5-6, n=3) VML. Meat physicochemical quality traits and consumer responses (n=389) on palatability and VML liking, and purchase intent were evaluated. The experiment was in RCBD. ANOVA, Duncan's multiple mean comparisons, and correlation coefficients were determined.

Results

VML correspond to crude fat (r=0.91, p<0.01), but both were reversely related to moisture content (r=-0.75 and -0.91, p<0.01, respectively). As VML increased, ash (p<0.05) and protein (p=0.072) decreased, pH and b* increased (p<0.05), but drip, cooking (p<0.05) and thawing (p=0.088) losses decreased. Among treatments, muscle fiber diameter, sarcomere length, total and insoluble collagen contents, L*, and a* did not differ (p>0.05). Compared to the others, HM had lower collagen solubility percentage (p<0.05), but similar (p>0.05) Warner-Bratzler Shear Force (WBSF). No differences (p>0.05) were found in juiciness, overall flavor, oiliness, and overall acceptability, but HM was more tender (p<0.05) than the others. Based on VML, consumers preferred MM to HM (p<0.05), while LM was similar to MM and HM (p>0.05). Corresponding to VML preference (r=0.45, p<0.01), consumers (83%) would (p<0.01) definitely and probably buy MM, over LM (74%), and HM (68%), respectively.

Conclusion

Increasing VML in pork LD altered its chemical composition, slightly increased pH, and improved WHC, thereby improving its tenderness acceptability. Marbling might reduce chewing resistance, as lower collagen solubility in HM did not impact tenderness acceptability and WBSF. While HM was rated as most tender, consumers visually preferred and would purchase MM.

Growth, carcass characteristics and meat quality of Chinese indigenous Yanan pig crossbred with Duroc and Berkshire genotypes

The objective of the present study was to evaluate the effects of crossbreeding on the growth, carcass characteristics and meat quality of Chinese native Yanan (YN) pig breed and related crossbreeds, including Duroc × Yanan (DY) and Duroc × (Berkshire × Yanan) (DBY). In total, 60 pigs (20 per breed) were used in the study. The results showed that both crossbreeds, especially DBY pigs, exhibited improved growth and carcass characteristics compared with those of purebred YN pigs. Moreover, the two crossbreeds, especially DBY pigs, produced acceptable meat-quality characteristics (normal pH and meat-colour values, high intramuscular fat content and water-holding capacity, acceptable muscle-fibre parameters, and strong pork flavour) similar to those of YN pigs. M. longissimus lumborum contained eight essential amino acids, with high contents in all pigs. C18:1, C16:0, C18:0, and C18:2 were the main fatty acids in M. longissimus lumborum in the three breeds, and a polyunsaturated:saturated fatty acid ratio of ~0.2 was observed in DBY and YN pigs. These results indicated that DBY pigs exhibit an acceptable total production performance and could be extensively used in commercial pig production to provide high-quality niche products.

Electrical stimulation or moisture infusion improves the eating quality attributes of loin and silverside cuts from female and immunocastrated male pigs

This study validated the effect of gender (female, immunocastrated male; n = 50), electrical stimulation (none or 150 mA constant current for 30 s at 2 min post-slaughter) and ageing period (2 or 14 d) on the eating quality of pork roast and stir fry sourced from the loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) and steak from the loin only. Moisture infusion was applied to 2 d aged, non-stimulated primals as a positive control treatment. Neither gender nor ageing period influenced (P > 0.05) eating quality. Electrical stimulation and moisture infusion were each effective interventions in improving pork eating quality, but their effects were inconsistent between the five cuts evaluated. No interventions achieved the fail rate target of <10% for quality grade for all cuts, indicating that additional interventions are needed to enable industry to consistently deliver high quality pork.

Validating post-slaughter interventions to produce consistently high quality pork cuts from female and immunocastrated male pigs

Eating quality attributes of pork loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) from female and immunocastrated male carcases hung from either the Achilles tendon or aitchbone, aged for either 2 or 7 days post-slaughter and cooked as roasts, stir fry and steak (loin only) (n = 25/gender) was assessed. A positive control treatment of moisture infusion (10% injection rate) was applied to Achilles hung sides with cuts aged for 2 d post-slaughter. Neither gender nor ageing period influenced consumer sensory scores. Beneficial effects of aitchbone hanging on eating quality compared with Achilles hanging were largely observed after 2 d ageing, with improvements (P < 0.05) in overall liking scores found for loin stir fry and silverside stir fry and roasts. Overall liking scores of all cuts, except silverside stir fry, were increased (P < 0.05) when moisture infused compared with those from aitchbone-hung sides. However, targeted fail rates of <10% were not consistently achieved across all cuts evaluated.

Influence of Duroc breed inclusion into Polish Landrace maternal line on pork meat quality traits

Crossbreeding with Duroc breed allows to improve meat quality, but no data is available regarding specific influence of Duroc breed on characteristics of meat in the case of crossbreeding with various breeds. The aim of the present research was to evaluate the effect of crossbreeding Polish Landrace dames with Duroc sires on quality features of meat in reference to Polish Landrace breed. The objects of the study were Longissimus dorsi lumborum pork muscles obtained from Polish Landrace breed and Polish Landrace x Duroc crossbreed animals. Sarcomere length measurements were conducted using microscopic method and basic chemical composition measurement was analyzed using spectrophotometric scanning. Texture analysis of meat samples, performed after thermal treatment was expressed by Warner-Bratzler shear force and color analysis was obtained using CIE L*a*b* color system. No differences in sarcomere length, shear force as well as components of color values between pork meat originated from Polish Landrace breed and Polish Landrace x Duroc crossbreed were observed. Analysis of basic chemical composition revealed higher fat and lower ash contents in the case of meat of Polish Landrace breed animals. It was concluded that the actual impact of breed on meat characteristics is possibly altered by other factors. It may be suggested that influence of basic chemical composition on color of meat is breed-related.

Culinary and technological suitability of pork obtained from three-way cross fatteners (Landrace x Yorkshire) x Duroc and (Landrace x Yorkshire) x Hampshire

The aim of the study was to evaluate the culinary and technological value of meat obtained from three-way cross fattening pigs, i.e. [Landrace (L) x Yorkshire (Y)] x Duroc (D) and [Landrace (L) x Yorkshire (Y)] x Hampshire (H). The study was carried out in spring and summer on 60 pigs divided in 2 genetic groups: (LxY) x D and (LxY) x H. The rearing and pre- and post-slaughter conditions were the same for all animals. Slaughter and post-slaughter handling of the carcasses was in accordance with the procedure in use at the meat plant. The research material was similar in terms of hot carcass weight (85.14 ±2.90 kg and 85.31 ±3.29 kg) and lean meat content (56.50 ±2.71% and 56.98 ±1.99%) within each genetic group, i.e. (LxY) x D and (LxY) x H. The significant, highly unfavourable means obtained for meat quality traits in the case of the (LxY) x H pigs, in terms of both culinary and technological suitability for processing, clearly indicates that the Hampshire breed should not be used as a paternal component in mass production of fatteners. In the case of the (LxY) x D fatteners, the highly favourable values for meat quality traits, of importance to both the consumer and the meat industry, clearly support the use of the Duroc breed as a paternal component.

Diet composition and slaughter age up to 24weeks have minimal impact on pork eating quality of loin steaks and silverside roasts from female pigs

Female crossbred pigs were randomly allocated at 16weeks of age to one of three dietary treatments (A: corn and soybean meal; B: wheat and canola meal; C: wheat and sorghum) matched for digestible energy (13.6MJ DE/kg) and total lysine (0.93-0.95%) and fed for 4, 5 or 8weeks, respectively, prior to slaughter. Loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) were obtained from 20 pigs per dietary treatment group and prepared into steaks and roasts, respectively, for consumer evaluation with ageing treatments of 7 and 28days post-slaughter allocated within muscle. Neither dietary treatment/age at slaughter nor ageing treatment influenced sensory traits of either cut. Intramuscular fat levels were also not influenced by dietary treatment. Higher (P<0.001) fail rates for silverside roasts compared with loin steaks indicate that different interventions are needed at a cut level to optimise pork eating quality consistency and consumer expectations.

The effects of two methods of increasing age at slaughter on carcass and muscle traits and meat sensory quality in pigs

The aim of this study was to investigate the effects of a 30-day increase in age of pigs slaughtered at 110 kg body weight (BW) on carcass and m. longissimus dorsi (LD) and m. biceps femoris (BF) traits, and meat sensory quality. A total of 60 pigs from two genotypes: synthetic line ✕ (Large White ✕ Landrace) (SL) and Duroc ✕ (Large White ✕ Landrace) (D) were used, each genotype containing five groups of six littermates (three castrated males and three females). At the average BW of 30 kg, littermates of the same sex were allocated to three groups. Pigs of group AL were offered ad libitum a standard growing-finishing diet (13·6 MJ/kg digestible energy, 9·5 g/kg of lysine) from 30 up to 110 kg BW. The R1 pigs received the same diet at 0·75 of the ad libitum intake of their AL littermates. The R2 pigs were submitted to both energy and protein restrictions in order to get the same growth rate as the R1 pigs and the same body composition as the AL pigs. Results were similar in both genotypes. In agreement with the protocol, age at slaughter was increased by 30 days in R1 and R2, and AL and R2 pigs had comparable carcass composition. Compared with AL, average daily gain was decreased in R1 and R2 pigs, and food efficiency was decreased in R2, but remained unaffected in R1 pigs. Intramuscular fat (IMF) concentration was decreased in the R1 pigs, especially in BF (15·5 v. 19·7 mg/g), while it was increased in the LD of the R2 pigs, particularly in the D animals (24·2 v. 17·4 mg/g), compared with AL pigs. Meat quality parameters (rate and extent of pH fall, reflectance and drip loss) were similar in the three feeding regimens. The taste panel did not find any significant difference between feeding regimens for tenderness, juiciness, flavour, flour sensation after mastication and mouth coating of the meat, despite the differences reported in IMF concentration. This suggests that, for the genotypes used in this experiment, an increase of 30 days in the age at slaughter greatly influences the carcass and/or the muscle chemical composition, depending on the feeding strategy applied to reduce the growth rate but does not strongly modify the meat eating quality.

Meat quality of Large White pig genotypes selected for components of efficient lean growth rate

Responses in carcass composition and meat quality after seven generations of selection for components of lean growth rate were examined in a population of Large White pigs. There were four selection groups in the study, with divergent selection for lean growth rate on ad libitum (LGA) or restricted (LGS) feeding regimes, lean food conversion ratio (LFC) and daily food intake (DFI). In generations six and seven, two offspring from each of 10 sires, within each selection line, were to be allocated for half-carcass dissection and measurement of meat quality. There were 320 animals in the study, with 40 animals from each of the high and low selection lines and, within each selection line, two offspring per sire.

Responses in carcass composition were similar in the three selection groups given food ad libitum, but rates of lean and fat growth rate differed between selection lines. Intramuscular fat content was reduced with selection for high LGA and high LFC but was increased with selection for low DFI (-1·7 and -3·2 v. 2·7 (s.e.d. 0·7) mg/g), which was unexpected given the higher carcass fat content of the low DFI line, relative to the high line (249 v. 190 (s.e.d. 7) g/kg). Muscle colour was darker, as measured by trained sensory panel assessment, in selection lines which reduced the rate of fat deposition to achieve a leaner carcass (high LFC and low DFI) but there was no response in muscle colour with selection for LGA (0·4 and 0·3 v. 0·0 (s.e.d. 0·1)). Responses in muscle shear force (5·3 v. 4·4 (s.e.d. 0·4) kg) and flavour liking (4·0 v. 4·3 (s.e.d. 0·12)) were limited to the LGA and LFC selection groups, respectively. There were no significant responses in muscle moisture content, muscle pH or myofibrillar fragmentation index, nor were there any responses in meat quality with selection on LGS. Therefore, decreasing the rate of fat deposition was associated with darker meat and increasing the rate of lean growth was associated with higher shear force. There were selection strategy specific responses in the fatty acid composition of intramuscular fat, which may have contributed to the responses in eating quality.

In general, responses in meat quality were small, such that incorporation of meat quality traits in selection objectives, which are primarily focused on increasing the efficiency of lean meat production, may not be necessary. However, it would be pertinent to evaluate periodically genotypes of breeding companies for muscle quality traits.

Carcass Performance, Muscle Fiber, Meat Quality, and Sensory Quality Characteristics of Crossbred Pigs with Different Live Weights

In order to attain heavier live weight without impairing pork or sensory quality characteristics, carcass performance, muscle fiber, pork quality, and sensory quality characteristics were compared among the heavy weight (HW, average live weight of 130.5 kg), medium weight (MW, average weight of 111.1 kg), and light weight (LW, average weight of 96.3 kg) pigs at time of slaughter. The loin eye area was 1.47 times greater in the HW group compared to the LW group (64.0 and 43.5 cm(2), p<0.001), while carcass percent was similar between the HW and MW groups (p>0.05). This greater performance by the HW group compared to the LW group can be explained by a greater total number (1,436 vs. 1,188, ×10(3), p<0.001) and larger area (4,452 vs. 3,716 μm(2), p<0.001) of muscle fibers. No significant differences were observed in muscle pH45 min, lightness, drip loss, and shear force among the groups (p>0.05), and higher live weights did not influence sensory quality attributes, including tenderness, juiciness, and flavor. Therefore, these findings indicate that increased live weights in this study did not influence the technological and sensory quality characteristics. Moreover, muscles with a higher number of medium or large size fibers tend to exhibit good carcass performance without impairing meat and sensory quality characteristics.

Studies on Intramuscular Fat Percentage in Live Swine Using Real-time Ultrasound to Determine Pork Quality

In the modern pork industry, selection of high intramuscular fat (IMF) in pigs is necessary to improve pork quality. Ultrasound has been used previously to predict subcutaneous fat thickness and IMF in the longissimus muscles of line pigs and Real-time ultrasound has also been reported as a reliable method for estimating IMF in live pigs. So we estimate the correlation between meat quality traits and IMF percentage to investigate the possibility of utilizing real-time ultrasound technology for predicting IMF percentage in line pigs to improve pork quality. The genetic and phenotypic correlations for chemical intramuscular fat (CIMF) and ultrasound intramuscular fat (UIMF) were estimated to be 0.75 and 0.76, respectively. These results suggest that genetic factors strongly influence meat quality. The genetic and phenotypic correlation between UIMF and CIMF were 0.75, 0.76, respectively. The heritability of UIMF and CIMF were 0.48 and 0.50, respectively. So we concluded that CIMF can be replaced with UIMF and Ultrasound machines can be used to test IMF in live swine. In future, UIMF can be utilized to improve pork quality as an alternative to CIMF.

Effects of soyabean meal- or whey-based diets on lipid metabolism in weaned piglets

The present study aimed to test the hypothesis that dietary protein source influences lipid metabolism-related parameters weaned piglets. The effects of soyabean meal (SB) and whey proteins (WP) on gene expression of several genes involved in the lipogenic process in liver, visceral (VAT) and subcutaneous (SAT) adipose tissues, plasma insulin concentration and fatty acid (FA) profile were investigated in 18 weaned piglets. Weaned piglets were fed one of two diets containing either SB or WP as the main protein source. Following a 10-h fasting period, plasma insulin concentration and FA profile were assessed at 56 and 72 days of age, whereas gene expression in liver, VAT and SAT was assessed at 72 days of age. Plasma insulin concentration was not affected by diet, although it was 40% lower in SB fed pigs. The SB pigs had lower 14:0 (p < 0.01) and higher 18:3n-3 (p < 0.001) levels in plasma in comparison with WP pigs. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. Gene expression of sterol regulatory element-binding protein 1 (SREBP-1) in liver and VAT were lower (p < 0.01 and p < 0.05, respectively) in SB compared to WP fed piglets, but no differences occurred in SAT. No changes were observed in sterol regulatory element-binding protein 2, liver X receptor, peroxisome proliferator-activated receptors α and γ and plasminogen activator inhibitor 1 mRNA levels, either in liver or in adipose tissues. In conclusion, dietary protein source, accompanied likely by side alterations in the dietary composition, affects lipid metabolism in pigs through the downregulation of SREBP-1, which is a crucial determinant of lipogenic process.

Adiponectin decreases lipids deposition by p38 MAPK/ATF2 signaling pathway in muscle of broilers

Adiponectin is an adipokine hormone that influences glucose utilization, insulin sensitivity and energy homeostasis. To investigate the effect of adiponectin on lipids deposition in broilers, rosiglitazone and dexamethasone were used to treat broilers. A total of 120 twenty-three-day-old male Cobb broilers were randomly divided into 3 groups for 3 weeks of drug treatment. Serum adiponectin level and fatty acid composition in muscles were measured. Adiponectin, adiponectin receptors (adipoR1, adipoR2) and lipid metabolism-related genes expression levels in muscles were measured using real-time PCR. Western blot was used to measure the expression levels of lipid metabolism-related proteins and the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK)/activating transcription factor 2 (ATF2) pathway marker proteins. Rosiglitazone increased serum adiponectin concentration and the expression levels of adiponectin and adipoR1 (P < 0.05), while dexamethasone had the opposite effect. Intramuscular fat content, total fatty acid, saturated fatty acid and monounsaturated fatty acid reduced in the rosiglitazone treatment group (P < 0.05). In the rosiglitazone treatment group, the expression levels of lipogenic genes and proteins decreased in the muscles, whereas the expression levels of lipolysis genes increased. Meanwhile, the phosphorylation levels of p38MAPK and ATF2 increased with supplementation of rosiglitazone and decreased in the dexamethasone treatment group (P < 0.01). These results indicated that rosiglitazone and dexamethasone could regulate adiponectin expression in muscle of broilers and adiponectin had an anti-lipogenic effect by p38 MAPK/ATF2 signaling pathway.

Injection of water and polyphosphate into pork to improve juiciness and tenderness after cooking

Two injection levels (5 and 10%) and three concentrations of polyphosphate (0, 3 and 5%) were used in 64 pork loin portions to assess the influence of polyphosphate injection on eating quality of pork steaks cooked by grilling to a centre temperature of 72.5 or 80°C and assessed by a trained ten member sensory panel. Polyphosphate improved water holding, and generally produced more tender and more juicy meat than control steaks, although pork flavour intensity was reduced and abnormal flavour intensity increased. Raising the centre temperature from 72.5 to 80°C increased the cooking loss from 35 to 42%, reduced tenderness, juiciness and abnormal flavours and increased pork flavour intensity. Steaks containing 5% polyphosphate and cooked to 80°C were more tender and as juicy as steaks without polyphosphate cooked to the lower centre temperature. These effects were generally larger than those that can be achieved `naturally' by, for example, changing diets and breeds but whether the technology will be utilised in an increasingly `additive free' climate is debatable.

The increased intramuscular fat promoted by dietary lysine restriction in lean but not in fatty pig genotypes improves pork sensory attributes

Sixty entire male pigs from 2 distinct genotypes (30 Alentejano purebred, an autochthonous fatty genotype, and 30 commercial crossbred pigs, a lean genotype) were used to investigate the effects of dietary CP reduction and low-Lys levels on growth performance, carcass traits, and meat quality. Pigs with 59.9 ± 2.0 kg BW were randomly assigned within each genotype to 1 of 3 diets [normal CP diet (control), reduced CP diet adjusted for Lys (RPDL), and reduced CP diet not adjusted for Lys (RPD)] as a 2 × 3 factorial arrangement of treatments with 10 individually fed pigs per treatment. Pigs were slaughtered at 93.4 ± 2.4 kg BW. The results showed that intramuscular fat (IMF) content of longissimus lumborum muscle was greater in Alentejano than crossbred pigs (5.0 vs. 2.4%). The RPDL had no effect on IMF content, ADG, backfat thickness, and loin weight in both genotypes. The RPD promoted the increase (P < 0.05) in IMF content in crossbred (∼50%) but not Alentejano pigs, which indicates that Lys restriction can mediate the effect of RPD. Within crossbred pigs, meat obtained from pigs fed RPD had an increased IMF content (+1.3%) and a tendency for greater sensory scores (tenderness, juiciness, flavor, and acceptability) than those fed the control. The IMF content was positively correlated to flavor in Alentejano genotype (P < 0.05) but not in crossbred pigs. Alentejano and crossbred pigs had a greater tendency to deposit 18:1c9 and SFA, respectively. Despite the contribution of fatty acid composition to flavor, its influence on pork acceptability was more noticeable in crossbred than Alentejano pigs. In conclusion, the increased IMF promoted by dietary CP reduction in lean but not in fatty pig genotypes during the growing-finishing period is likely due to Lys limitation, which seems to enhance eating quality of pork.

Comparison of pork quality and sensory characteristics for antibiotic free yorkshire crossbreds raised in hoop houses

The objective of this study was to compare pork characteristics and to determine consumer acceptability of pork chops from antibiotic free Yorkshire crossbreds sired by Berkshire (BY), Large Black (LBY), Tamworth (TY) or Yorkshire (YY) boars and reared in hoop houses. The experiments were conducted at the North Carolina Agricultural and Technical State University (NCA&TSU) Farm in Greensboro, NC and the Cherry Research Station Center for Environmental Farming Systems (CEFS) Alternative Swine Unit in Goldsboro, NC (source of antibiotic free Yorkshire sows used at both places). Twenty-four sows were artificially inseminated at each location in each of three trials. Litters were weaned at 4 wks old, and reared within deep-bedded outdoor hoop houses. To compare pork characteristics, 104 randomly selected animals were harvested at a USDA-inspected abattoir at approximately 200 d of age. Variables measured included pH, color score, L*, a*, b*, marbling score, drip loss, hot carcass weight, backfat thickness (BF), loin muscle area (LMA), and slice shear force. Sensory panel tests were also conducted at two time periods. The data was analyzed with GLM in SAS 9.01 including location, trial, and sire breed as fixed effects. Backfat thickness, LMA, color score and a* were different among breeding groups (p<0.05). The LBY pigs had thicker backfat and smaller LMA than the other breed types. The TY and YY had less backfat than all other breed groups. Color score was lower for YY than BY and LBY but intermediate for TY. The a* was lower for TY than other breeds except LBY which was intermediate. For one sensory panel test, YY pork was more preferred overall as well as for juiciness and texture compared to BY and LBY (p<0.05), but no impact of breed type was noted for the other test, with values similar for BY, LBY, TY and YY pork. This information may help small farmers make decisions about breed types to use for outdoor production.

The response of various muscle types to a restriction -re-alimentation feeding strategy in growing pigs

Muscle lipid concentration is known to influence pork eating quality. This study aimed at evaluating the effect of a restriction-re-alimentation feeding strategy on intramuscular fat deposition in pigs. A total of 70 Duroc × (Large White × Landrace) pigs (castrated males and females) were used. Ten pigs were first slaughtered at 30 kg live weight (LW) to determine initial body and muscle composition. From 30 to 80 kg LW (growing period), pigs were either fed ad libitum (AL) or restricted to 70% of the ad libitum intake of AL pigs (RA). From 80 to 110 kg LW (finishing period), both AL and RA pigs were fed ad libitum. In each group, pigs were slaughtered at 80 kg (n = 10) and at 110 kg (n = 20) LW. During the growing period, the growth rate of RA pigs was reduced by 30% (P < 0.001) compared with AL pigs. During the finishing period, RA pigs had a 7% (P = 0.09) higher growth rate than AL pigs due to compensatory feed intake (+14%). Plasma insulin-like growth factor-1 concentration was lower in RA pigs at 80 kg LW, but markedly increased after re-alimentation up to the level observed in AL pigs (P < 0.001). At 80 kg, the leaner carcasses of RA pigs resulted from a more pronounced reduction in fat than in lean tissue deposition rates. Re-alimentation of RA pigs increased fat tissue deposition (+160% for females, P < 0.01) but not lean deposition in the carcass, leading to limited differences in carcass composition between RA and AL pigs at 110 kg LW. Regarding tissue deposition rates, the response to feeding strategy differs between muscles. In the m. biceps femoris (BF), restriction affected lipid (-50%, P < 0.001) and protein (-25%, P < 0.001) deposition, whereas re-alimentation increased lipid (+62%, P < 0.05) but not protein deposition rates. At market weight, the extent of the difference in BF lipid concentration between RA and AL pigs was strongly reduced, but still significant. By contrast, in the m. longissimus, restriction decreased protein but not lipid deposition, whereas neither of them was modified during re-alimentation. Therefore, an increased muscle lipid concentration at 110 kg LW could not be reached in RA pigs. Modifications of onset and/or duration of restriction and re-alimentation periods should be tested to optimise effects on muscle lipid deposition and thereby achieve improved pork quality.

Pork meat quality affects peptide and amino acid profiles during the ageing process

Twenty pork carcasses were classified in different pork meat qualities: red, firm and non-exudative (RFN), pale, soft and exudative (PSE), red, soft and exudative (RSE) and dark, firm and dry (DFD) meat. The content of peptides and free amino acids during the ageing process was analysed and compared within quality classes. Four peptide fractions were isolated through cation-exchange and reverse-phase chromatography. The main significant differences among qualities were obtained for peptide fractions 3 and 4. Peptide fraction 3 at 4 days and peptide fraction 4 at 2 h postmortem were higher in the ideal pork quality (RFN) than in the other quality classes. The ageing of pork meats produced a general increase in all free amino acid concentrations for the studied quality classes except for Gln, β-Ala, Taurine and Orn and the dipeptides carnosine and anserine. The DFD class showed higher increases in Lys, Ala and Met probably due to the activation of neutral aminopeptidases.

Effect of nutritional regimen including limit feeding and breed on growth performance, carcass characteristics and meat quality in beef cattle

McGregor, E M., Campbell, C. P., Miller, S. P., Purslow, P. P. and Mandell, I. B. 2012. Effect of nutritional regimen including limit feeding and breed on growth performance, carcass characteristics and meat quality in beef cattle. Can. J. Anim. Sci. 92: 327–341. The effects of nutritional management regimen and breed on growth performance, carcass attributes, and meat quality were evaluated in 68 British (BRIT) and Continental (CONT) crossbred steers, managed on one of three nutritional regimens: (1) ad libitum access to a 77% corn diet (ALGRAIN), (2) limit feeding initially of the 77% corn diet, followed by ad libitum access to the 77% corn diet (LFGRAIN), and (3) limit feeding initially of a 90% haylage diet, followed by ad libitum access to the 77% corn diet (LFHAYL). Nutritional regimen by breed interactions (P<0.02) were present for average daily gain, dry matter intake (DMI), gain to feed, and shear force. LFHAYL regimen decreased gains to a greater extent for BRIT steers than CONT steers managed on ALGRAIN or LFGRAIN. Feed intakes were similar across nutritional regimens for CONT steers, while DMI was depressed in BRIT on LFHAYL as compared with steers started on ALGRAIN or LFGRAIN. Gain to feed was greater in BRIT cattle on LFGRAIN vs. ALGRAIN, while gain to feed was similar in CONT started on grain (ALGRAIN, LFGRAIN). Shear force was lower for beef from LFHAYL BRIT vs. beef from BRIT on ALGRAIN or LFGRAIN, while the converse was true for CONT. Limit feeding of a high-energy diet may be appropriate for cattle of British background to reduce feed input costs, while ensuring tenderness.

Effects of muscle cortisol concentration on muscle fiber characteristics, pork quality, and sensory quality of cooked pork

The effect of muscle cortisol concentration on muscle fiber characteristics and technological and sensory quality of pork was investigated. With the exception of the percentage of type IIA fibers, muscle fiber characteristics were not associated to cortisol levels. However, muscle cortisol concentration was positively associated with muscle pH(24h) (r = 0.23, P<0.05) and negatively associated with drip loss (r = -0.49, P<0.001), lightness (r = -0.24, P<0.05), shear force (r = -0.25, P<0.05), and texture profile analysis-hardness (r = -0.35, P<0.01). Additionally, the water-holding capacity of meat samples was affected by cortisol levels, with lower cortisol concentrations associated with less tender samples. These results indicate that the concentration of cortisol in the muscle is related with meat quality as well as the sensory quality of cooked pork.